Wireless communication networks, as well as security and emergency communication networks are well known in the prior art, however, the communication links within the system have a fixed configuration determined during the system's installation. Such systems are described for instance by Burns (U.S. Pat. No. 5,129,096). A system that remedies this lack of flexibility and the lack of autonomous system reconfiguration in response to changes in the environment or to the number of operational communication nodes in a given network was disclosed in the above cited application.
In practical situations, additional network versatility has been found to be highly desirable. For instance, in current link layered wireless networks, messages between subscriber units that are not within a predetermined link hierarchy, namely, the then preferred routing path between any one of the two subscribers units and the central monitoring station does not contain the other subscriber unit, need to be routed through the central monitoring station and thus, a less than optimized routing is utilized. In the present invention apparatus and methods as well as routing algorithms are provided that optimize and update such routing between any two subscribers units in the network.
Under special circumstances, it is also desirable to shift the network's central station functions within a subset of the subscribers units. In the prior art, this required recommissioning of the network to rededicate a new central or command station. This process is time consuming and thus creates excessive network down time, a highly detrimental feature in wireless communication networks. The present invention allows for the autonomous shifting of the network's command functions between a predetermined subset of the network's communication nodes.
Furthermore, prior art security networks can be easily disabled or compromised by determined foes, via intentional jamming and injection into the network of false messages. The present invention increases the wireless communication network's ability to withstand such intentional interferences.
The use of encryption algorithms to increase network security and prevent unauthorized access to messages transmitted in a wireless communication network are well known. However, with the advent of powerful computing platforms, deciphering of encryption algorithms has become more feasible, particularly when sufficient traffic can be analyzed. One way to defeat such deciphering attempts is by changing the encryption algorithms often and in a random manner. However, one must assure that the network in its entirety switches to a new encryption algorithm simultaneously. This is difficult to achieve in a traditional wireless communication network due to the time it takes for messages to be transmitted through the network, and particularly, the time it takes for messages to positively reach remote communication nodes. The instant invention provides a method and apparatus to assure that the shift between encryption algorithms occurs simultaneously in the wireless communication network.
Similarly, the instant invention provides for hybrid communication networks in which localized sub networks, often operating at different transmission frequencies than the master network, but not necessarily so, can be incorporated into a single network. One such embodiment involves a master network of fixed communication nodes that is used by a sub network of mobile communication nodes to establish a self reconfiguring unified network. Another embodiment allows the incorporation of established networks, let say with older technology, such as nodes having slower modems than currently available, into a master network of state of the art communication nodes, where the modern communication nodes can communicate between themselves at one frequency and act as a central destination to localized older networks operating at other frequencies, thereby creating a single network which is self reconfiguring.